MM Science Journal, March 2015

EVALUATION OF HARDNESS CURVES OF MULTILAYER WELDS OF CREEP RESISTANT STEEL 1.6946 USING SAW METHOD TO THE “ULTRA” NARROW GAP

LUKAS HOLUB, JIRI DUNOVSKY, JAN SUCHANEK
Keywords: submerge arc welding | narrow gap | low alloysteel | hardness HV10 | turbine | ro

The paper deals with partial verification of mechanical properties (through waveform measurements hardness HV10) obtained after SAW multi-pass welding in "ultra" narrow gap. Simulated homogenous welds of high pressure (HP) turbine rotors (30CrMoNiV5-11) formed with various types of filler materials (TOPCORE 838 B Thermanit MTS 616) using the same temperature cycle and subsequent heat treatment were test (…)

ACTIVE VIBRATION CONTROL FOR A FREE PISTON STIRLING ENGINE GENERATOR USING A VOICE COIL ACTUATOR

ALI HASSAN, ANGEL TORRES-PEREZ, STEFAN KACZMARCZYK, PHIL PICTON
Keywords: type stirling engine | active vibration damping | linear quadratic control | feedback-feedforward with zero-placement | voice coil actuator | electrical current control | effect of time delays

This work presents the study of active vibration control for a FPSE/LA engine to ensure a reliable engine operation within a broader range of operation frequencies [50 ± 3 Hz] complying with new regulations. An ATMD is discussed as a potential solution for increasing the operational envelope from original frequency requirements of [50 ± 0.5 Hz] to the new range while maintaining vibration amplitudes bel (…)

EXPERIMENTAL INVESTIGATION ON THE EFFECT OF INJECTING WATER TO THE AIR TO FUEL MIXTURE IN A SPARK IGNITION ENGINE

DANIEL BUSUTTIL, MARIO FARRUGIA
Keywords: thermal engineering | ignition internal combustion engines | mechatronics | automotive applications | water injection

Water injection is a means of internal cooling of the engine. During combustion, excess temperatures generated are absorbed by water as latent heat. Optimum water injection quantities were found to be about 0.015 ml to 0.031 ml of water per cycle on a 592 cc SI engine. The experiments were carried out by tapping the fuel injector signal and designing a circuit to inject water at the instant petrol is in (…)

MODIFIED HAMILTONIAN ALGORITHM FOR OPTIMAL LANE CHANGE WITH APPLICATION TO COLLISION AVOIDANCE

YANGYAN GAO, MATHIAS LIDBERG, TIMOTHY GORDON
Keywords: collision avoidance | vehicle control | active safety | vehicle dynamics | intelligent vehicle | optimal control

This paper deals with collision avoidance for road vehicles when operating at the limits of available friction. For collision avoidance, a typical control approach is to: (a) define a reference geometric path that avoids collision; (b) apply low-level control to perform path following. However, there are a number of limitations in this approach, which are addressed in the current paper. First, it is typ (…)

ROTOR DESIGN AND OPTIMIZATION OF SYNCHRONOUS RELUCTANCE MACHINE

JAN BARTA, CESTMIR ONDRUSEK
Keywords: synchronous reluctance machine | transverse-laminate rotor | electromagnetic model | finete element analysis | optimization | torque ripple

The world has a bottomless appetite for electricity. Much of this electricity is used to power electric motors. Thanks to that electric motors represent a huge potential for energy savings. Synchronous reluctance machines are promising electric machines for energy savings. Key to success of synchronous reluctance machines is laying in elimination of rotor losses. This article deals with the design of sy (…)

SYSTEM FOR SUPPORT THE DESIGN AND OPTIMIZATION OF RECONFIGURABLE MANUFACTURING SYSTEMS

BRANISLAV MICIETA, VLADIMIRA BINASOVA, MICHAL HALUSKA
Keywords: reconfigurable manufacturing systems | cladistics | manufacturing configurations | engineering design of production machines

This paper is an experimental study of the system for support the design and optimization of reconfigurable manufacturing systems (RMS), which contains from the basic components of the proposed solution. Individual parts communicate with each other and exchange information which is necessary for implement required tasks. In addition, this paper also investigates the reconfigurable manufacturing systems, (…)

TRANSIENT THERMAL ANALYSIS OF SMALL SQUIRREL CAGE MOTOR THROUGH COUPLED FEA

ROMAN PECHANEK, VLADIMIR KINDL, BOHUMIL SKALA
Keywords: induction motors | machine modelling | thermal analysis | Simulation | computational fluid dynamics | finite element analysis

The thermal analysis is necessary in design process of new electric motor. During motor design process is necessary to know temperatures of induction motor’s (IM’s) construction parts. The calculated temperatures in all motor parts should be lower than critical temperatures. This paper deals with free-dimensional (3D) transient thermal analysis of small squirrel cage motor/induction motor. The design of (…)

RESISTANCE SPOT WELDING OF MAGNESIUM ALLOY AZ61

TOMAS KRAMAR, PETR VONDROUS, MARIE KOLARIKOVA, KAREL KOVANDA, LADISLAV KOLARIK, MICHAL ONDRUSKA
Keywords: resistance spot welding | RSW |   Mg alloy | AZ61 | solidification cracking

Resistance spot welding (RSW) was used to weld Mg alloy AZ61A. To research weldability of this alloy many welding parameters, e.g. current, time, pressure, have been tried in wide range on the welding source DALEX PMS 11 – 4. Visual check was followed with metallography, tensile test etc. Some defects as solidification, liquation cracks, porosity were found. The creation of imperfections was found to be (…)

MODEL-BASED SYSTEM ASSESSMENT OF THERMOELECTRIC ENERGY HARVESTING FROM THE EXHAUST GAS PIPE OF OIL-FIRED HEATINGS

MARCO NESARAJAH, FELIX FELGNER, AND GEORG FREY
Keywords: thermoelectric generator | oil-fired heating | energy harvesting | system assessment | Modelica®

We present a methodology to assess the design of ther-moelectric Energy Harvesting Systems (EHS) from exhaust gas pipes. In this application, thermoelectric generators (TEGs) are used to generate electricity using a temperature difference, based on the Seebeck Effect. The hot side temperature is given bythe waste heat in theexhaust gasof an oil-fired heating system and, at the cold TEG side, two differe (…)

ESTIMATION OF BACK EMF FOR PMSM AT LOW SPEED RANGE

KONRAD URBANSKI
Keywords: sensorless control | permanent magnet synchronous motor (PMSM) | observer | variable speed drive | vector control | back electromotive force (back EMF)

In the paper is presented a comparison of three method of back electromotive force estimation. Presented structures: the observers and the simulator, are utilized to estimate the back electromotive force for speed range below single revolution per second. Theirs instantaneous values are used then to calculate the shaft position of the permanent magnets synchronous motor. Performance of such structures i (…)